The present invention relates to therapeutic devices and medical appliances that provide support or pressure to tissue. In particular, the invention relates to devices and appliances comprising open cell foam usefull in the treatment of diseases, disorders and injuries.
Patients suffering from injury or disease or recovering from surgery may be treated by the application of constant or intermittent pressure. Pressure is used to control swelling, increase blood flow, and immobilize tissue.
In cases of acute injuries, such as acute joint injury, three treatments are employed simultaneously. First, the injured region is chilled (such as with ice); second, pressure is applied using an elastic bandage; and third, immobilization is achieved using a splint. For example, an athletic trainer applies elastic wrap to an injured ankle or knee and then immobilizes the joint with a splint or bulky bandage. However, the application of elastic wrap may produce a wide range of pressures on the injured limb. The incorrect pressure may retard venous or arterial circulation and may contribute to thromboembolism; pressure that is too high can induce tissue ischemia that further injures the tissue.
More complex pressure devices are available to patients suffering from various venous, circulatory and peripheral vascular diseases. These devices typically consist of an inflatable bladder in the form of a sleeve that can be placed around all or a portion of a patient""s arm or leg. The bladder is connected to a pump that alternately inflates and deflates the bladder. In some such devices, the sleeve placed around the extremity includes a number of sequential bladders along the axial length of the sleeve to allow the sleeve to be inflated and deflated in a peristaltic manner along its length. By alternately inflating and deflating the bladder or bladders contained within the sleeve, circumferential pressure is applied to the patient""s extremity, thus aiding in the circulation of blood there through. Such systems are currently used to treat venous insufficiency, prevent deep venous thrombus and control lymphedema and improve tissue perfusion in patients with peripheral arterial disease.
Other medical devices such as catheters and tracheotomy tubes are placed into a body lumen and then held in place with an inflatable balloon at the distal end of the device. The balloon is subject to over-inflation, however, again resulting in possible damage to treated tissue.
In addition, current systems tend to be expensive and complex, frequently being coupled to feedback circuits to control changes in pressure. Compression systems have been known to malfunction and cause undesirable variability in or increase in the applied pressure. Even when such systems are controlled by the patient, they may be subject to incorrect operation resulting in over-inflation of the sleeve. For such a system used to correct venous insufficiency in a limb, for example, incorrect operation is at best painful and at worst results in loss of the limb. Finally, most patients complain of some level of pain during inflation due to the rapid increase in pressure against the extremity.
In view of the above, the need exists for therapeutic devices that are capable of applying pressure but which are unable to produce over-pressure at the site of damage or disease. Such devices should be simple to use, allow peristaltic pumping at a variety of pressures, and have the ability to apply heat or cold.
The present invention relates to therapeutic devices that provide support or pressure to tissue. In particular, the invention relates to such devices comprising open cell foam useful in the treatment of diseases and injuries. The open cell foam is in a relaxed or relaxed state until application of vacuum resulting in an evacuated state. The foam is engineered to produce a device that has characteristics that provide a maximum desirable pressure and that will avoid the possibility of over-pressure which can result in tissue damage or necrosis.
In a first aspect, this invention is a medical device for applying pressure to tissue comprising a body portion having a relaxed state and a contracted state, the body portion being configured to apply pressure to tissue in the relaxed state, the body portion adapted to contain a fluid; and a fluid controller fluidly connected to the body portion for removing fluid contained in the body portion, the body portion being configured to contract from the relaxed state to the contracted state upon removal of fluid from the body portion. The body portion may comprise foam and preferably comprises open cell foam. The body portion also may include a fluid impermeable outer coating. The medical device may also comprise a fluid source and a valve, the valve being connected between the body portion and the fluid source and fluid controller, the valve having a first position for connecting the body portion to the fluid controller and a second position for connecting the body portion to the fluid source. The fluid controller may be a vacuum source. The valve preferably is programmable and the valve may be programmed to switch between the first position and the second position. The medical device may comprise a bladder fluidly connected to a liquid wherein the liquid is hot or cold.
In a second aspect, this invention is a medical device for applying pressure to a human or animal limb comprising a body portion having a substantially cylindrical shape sized to fit over the limb, the body portion being adapted to contain a fluid and further having a relaxed state and a contracted state, the body portion being configured to apply pressure to the limb in the relaxed state, and a fluid controller fluidly connected to the body portion for removing fluid contained in the body portion, the body portion being configured to contract from the relaxed state to the contracted state upon removal of fluid from the body portion. The body portion may comprise open cell foam and may include a fluid impermeable outer coating.
In a third aspect, this invention is a medical device for applying pressure to tissue comprising a body portion having at least two separate compartments, each compartment having a relaxed state and a contracted state and being configured to apply pressure to tissue in the relaxed state, the compartments being adapted to contain a fluid, and a fluid controller fluidly connected to each compartment of the body portion for removing fluid contained in the body portion, each compartment being configured to contract from a relaxed state to a contracted state upon removal of fluid from the compartment. The device may include valves, the valves being connected between each compartment and the fluid source and fluid controller and having a first position for connecting the compartment to the fluid controller and a second position for connecting the compartment to the fluid source. Each compartment may be separately cycled between the first and second position of the at least one valve in a sequence so as to apply pressure to tissue in a peristaltic manner.
In a fourth aspect, this invention is a medical device for applying pressure to tissue comprising a body portion having a first region configured to apply a first pressure to tissue and a second region configured to apply a second pressure to tissue, each region having a relaxed state and a contracted state and capable of applying pressure to tissue in the relaxed state, the regions being adapted to contain a fluid, a fluid controller fluidly connected to the body portion for removing fluid contained in the body portion, each region being configured to contract from a relaxed state to a contracted state upon removal of fluid from the compartment, wherein the first pressure is not equal to the second pressure. The pressure of the first and second regions may form a gradient.
In a fifth aspect, this invention is a method of applying pressure to tissue comprising supplying, adjacent to the tissue, a device having a body portion, the body portion having a fluid impermeable exterior and a fluid containing interior; applying vacuum to the interior of the body portion to remove the fluid such that the body portion is in a contracted state; and removing the vacuum to the interior of the body portion to allow fluid to enter the interior such that the body portion is caused to expand to a relaxed state, the body portion in the relaxed state applying pressure to the adjacent tissue. The pressure may be alternately applied and removed from the tissue.
In a sixth aspect, this invention is a method of supporting a patient""s body in a bed or chair comprising supplying a patient supporting structure having a plurality of compartments, each compartment having a fluid impermeable outer portion and a fluid containing inner portion; applying a vacuum to the inner portion of a first compartment such that the first compartment is in a contracted state and pressure between a first portion of the patient""s body and the outer portion of the first compartment is reduced; removing the vacuum from the inner portion of the first compartment such that the first compartment is caused to expand to a relaxed state such that increased pressure is applied to the first portion of the patient""s body by the outer portion of the first compartment; applying a vacuum to the inner portion of a second compartment such that the second compartment is in a contracted state and pressure between a second portion of the patient""s body and the outer portion of the second compartment is reduced; removing the vacuum from the inner portion of the second compartment such that the second compartment is caused to expand to a relaxed state such that increased pressure is applied to the second portion of the patient""s body by the outer portion of the second compartment; and cycling between the applying steps and the removing steps in the first and second compartments so that the pressure applied to the first and second portion s of the patient""s body is varied.
In a seventh aspect, this invention is a method of holding a medical device in place in a body lumen comprising providing a device having a support element in communication with a fluid line; the support element having a relaxed state at ambient pressure and a contracted state at reduced pressure; removing fluid from the support element to produce the contracted state; advancing the device through the lumen with the support element in the contracted state; positioning the device at a desired location within the body lumen; and admitting fluid at ambient pressure to the support element, thus returning the support element to the relaxed state, the support element in the relaxed state being configured to provide pressure against the body lumen to hold the medical device in place.
In an eighth aspect, this invention is a medical device comprising a body portion comprising a material adapted to contain a fluid, the material having a first size when filled with the fluid and a second smaller contracted size when the fluid is removed, the material being selected to be in a relaxed condition when filled with fluid and to resist contraction to the second size when fluid is removed; and a fluid controller fluidly connected to the body portion, the fluid controller being configured to remove fluid from the body portion.
The therapeutic device of this invention offers numerous advantages over devices currently in use. The maximum compressive force that can be applied to a patient""s tissue is the force applied by the open cell foam in its relaxed state. By a proper selection of a foam with specific physical characteristics, it is possible to predetermine the amount of force to be applied to a patient""s limb, and thereby prevent discomfort, pain and injury that can occur by providing excess pressures to a limb or body tissue. As such, the devices of this invention do not cause discomfort or injury to the patient due to malfunction or improper operation. In addition, the present invention provides a simple and inexpensive way of achieving a peristaltic action on the limb of a patient suffering from circulatory or a peripheral vascular disease.